1. Field of the Invention
The present invention relates to vibratory apparatus and, more particularly, to an apparatus for controlled separation of a composite mixture by density and/or particle size.
2. Background Art
It is known to provide a vibratory conveying structure to separate composite mixtures including particles of different size and density. An exemplary use for such a structure is to separate accumulated materials in a wood yard. The composite mixture may include wood fiber, dirt, stones, steel and/or other materials that commonly are found around such an operation.
A typical prior system uses a vibrating trough to advance the composite mixture from a supply source to a discharge area. The flow path along the trough is interrupted by a drop-out opening. The composite mixture is directed from a first plateau across the drop-out opening so that the trajectory of certain of the particles is intercepted by a landing surface at the discharge side of the drop-out opening and beneath the elevation of the first plateau. A forced air supply is directed substantially parallel to the flow on the first plateau and propels additional low density particles onto the landing surface or second plateau. The more dense particles fall to the bottom of the structure for accumulation in a first area while the particles on the landing surface are conveyed to a second, separate area.
The air supply impinging on the particles falling off of the plateau into the drop-out opening has been generally ineffective in propelling the desired particles to the landing area. For example, the particles may be lodged together as clumps so that the force of the air stream is not sufficient to cause the particles to reach the landing area, though their individual weight dictates that they should follow the path of the low density material. As a result, an incomplete separation occurs. To attempt to break up the clumps, the air flow was increased with the result that heavy unwanted particles were propelled across the drop-out opening and onto the landing area.
Further, the prior structures have incorporated a landing area with a fixed dimension and orientation. Combining this shortcoming with a fixed drop-out opening severely limits the versatility of the apparatus. The dimensions of the drop-out opening and orientation of the landing must thus be chosen depending on one particular environment within which the apparatus is intended to be operated.
Also, the forced air supply systems in the prior structures have been generally unduly complicated.
The present invention is specifically directed to overcoming one or more of the above enumerated deficiencies known in the art.